Calcium hypochlorite, water-soluble zinc salts and coagulants that can be mixed safely with the two are known as compositions for disinfecting pools or spas and the like and inhibiting algae growth therein (see Patent Document 1).
A specific example of a coagulant is sodium aluminate, while specific examples of disclosed compositions include a composition containing 80 g of calcium hypochlorite, 10 g of zinc sulfate monohydrate and 10 g of sodium aluminate, and a composition containing 90 g of calcium hypochlorite, 5 g of zinc sulfate monohydrate and 5 g of sodium aluminate. Furthermore, a coagulant refers to that which has a function that coagulates particles dispersed in contaminated water and promotes precipitation thereof.